1. Field of the Invention
This invention relates to mountings for windshield wiper arms onto drive shafts and, more particularly, to a fine angular adjustment of a windshield wiper arm on a drum-head of a drive shaft.
2. Description of the Prior Art
In the automotive field, it has become reasonably standard practice to have at least two drive shafts extending outwardly along the edge of the windshield. Windshield wiper arms for use on said drive shafts have mounting heads with openings for receiving drumheads mounted on said drive shafts for securing the arms to the drive shafts. The standard that has been adopted for the drumheads or drive burrs calls for 84 parallel flutes or ribs being formed on the drumhead or drive burr with said flutes being equally spaced apart around the periphery of the drumhead. The standard mounting head opening for engagement with the drive burr has 42 flutes or ribs resulting in the arm being positionable on the shaft with an adjustment no finer than approximately 2.14 degrees. Therefore, when a wiper arm is attached to the drumhead, there is approximately a four degree difference between each successive location of the arm relative to the shaft. This results in the possibility that the wiper arm will be parked either on top of the belt line of the windshield or will be spaced from the belt line and in the field of vision of a person looking out of the windshield. Many different systems have been proposed for making a fine adjustment between adjacent settings of an arm on a drive shaft.